Model Output Discussion 29th December - Into mid-Winter.

[MKN]

Just now, TSNWK said:

And yesterday it was all 51 members supporting a E'ly in my view too much credence is given to these tweets, which appear to flip flop like a fish out of water, several times a day - rather disingenuous to folk who spend tine and effort detailing their thoughts, offering charts etc.

Ensembles often flip from one idea to another within the space of a run. For our island the models dont cover themselves in glory. Has always been the case. Partly though its the size of our country and the fact we are not part of a large landmass. Minor differences in the output can have a large effect on the weather we end up with.

[stewfox]

12 minutes ago, Ali1977 said:

This seals the chance of a very cold next week from the east but I still think the ECM had the best handle on things as it's still looking pretty close to what it's said over the last few days, only a few hundred miles out.  The GFS was way off and moved towards the ECMs thoughts so those saying the GFS has won are way off, infact I think the ECM has outperformed the GFS so far this winter.  Imagine if the GFS starts swinging colder on this run, is it out of the question I wonder!!!

Mats post change every 6hrs

Lets see what the GFS 6z brings and the follow on ECM UKMO

Nothing is nailed yet

[johnholmes]

For what it may be worth, or not! The 3 anomaly charts have two with the upper ridge centred ENE of the Uk with one having a ridge about the same but with its centre of gravity of the fairly smallish +ve anomaly just NW of Ireland.

links

http://www.cpc.noaa.gov/products/predictions/610day/fxus06.html

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Following Ed's comment after this, yes, it would keep generally fairly cold weather, little wind, varaibale cloud cover, mostly dry and frosts each evening into the following morning. Eventually IF the NOAA charts are correct then a somewhat milder outlook but that is probably at least 2 weeks away based on the current anomaly charts.

Edited January 11, 2017 by johnholmes

[Frosty.]

5 minutes ago, TSNWK said:

And yesterday it was all 51 members supporting a E'ly in my view too much credence is given to these tweets, which appear to flip flop like a fish out of water, several times a day - rather disingenuous to folk who spend tine and effort detailing their thoughts, offering charts etc.

Agreed, ensembles are fickle and support can easily grow again..this ain't over!

[mb018538]

Before people start laying into Matt for posting about all of yesterdays ECM members showing an easterly - does this morning's ECM not show an easterly? Yes it does:

People were just getting over-hyped with the cold 850s shown yesterday. The problem I think we will have is the cold pool of air will be removed before the easterly sets in - so while it will be cold, it won't be as cold as previously shown. Stop getting those knickers in a twist, and go with what's showing. It's not zonal, we are in the middle of winter, and there are some good blocks being put down.

[jvenge]

9 minutes ago, TSNWK said:

And yesterday it was all 51 members supporting a E'ly in my view too much credence is given to these tweets, which appear to flip flop like a fish out of water, several times a day - rather disingenuous to folk who spend tine and effort detailing their thoughts, offering charts etc.

Lol, that's because the model output changes several times a day and the chap only seems to talk about what they show.

[Methuselah]

2 minutes ago, johnholmes said:

For what it may be worth, or not! The 3 anomaly charts have two with the upper ridge centred ENE of the Uk with one having a ridge about the same but with its centre of gravity of the fairly smallish +ve anomaly just NW of Ireland.

links

http://www.cpc.noaa.gov/products/predictions/610day/fxus06.html

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

That suggests to me that, whichever of those solutions comes to pass, there'll be no 'mild mush' any time soon...On the contrary, in areas with lying snow, very low nighttime minima and freezing fog might be more the order of the day?

[jvenge]

1 minute ago, mb018538 said:

Before people start laying into Matt for posting about all of yesterdays ECM members showing an easterly - does this morning's ECM not show an easterly? Yes it does:

People were just getting over-hyped with the cold 850s shown yesterday. The problem I think we will have is the cold pool of air will be removed before the easterly sets in - so while it will be cold, it won't be as cold as previously shown. Stop getting those knickers in a twist, and go with what's showing. It's not zonal, we are in the middle of winter, and there are some good blocks being put down.

The risk, if it can be said to be one, is that the colder air stops in France and also sinks a little further south. The GEFS are showing this scenario, but no idea if it is right. Still plenty of time for upgrades/downgrades, though.

[Chris K]

6 minutes ago, jvenge said:

The risk, if it can be said to be one, is that the colder air stops in France and also sinks a little further south. The GEFS are showing this scenario, but no idea if it is right. Still plenty of time for upgrades/downgrades, though.

I think also that the key point to make, if we get to the stage of heights to our NE like that, is whether they eventually sink into Europe again, hold firm to allow potential retrogression, sit over the UK, or move further north to allow colder air to start flooding through Europe again and then westwards. As usual many options on the table can come from this. Whilst people may be a little dismayed at the lacklustre easterly uppers at first, it is the overall pattern going forward that I am more interested in. Fingers crossed and I will be happy unless slugs start making a comeback.

Edited January 11, 2017 by Chris K

[Nick F]

06z GFS still has the heavy snow signal on the back edge of Thursday's wave low running across the far south

[Frosty.]

Anyway, a lot of attention should be focussed on tomorrow, it's an upgrading situation in terms of classic rain to sleet to heavy wet snow across the south, the southeast could be the sweet spot tomorrow with a spell of heavy snow and several inches accumulating!

[MKN]

5 minutes ago, Frosty. said:

Anyway, a lot of attention should be focussed on tomorrow, it's an upgrading situation in terms of classic rain to sleet to heavy wet snow across the south, the southeast could be the sweet spot tomorrow with a spell of heavy snow and several inches accumulating!

I know its not the most accurate but gfs doesnt predict much lying snow for most of England.

[Tamara]

 

Same overall theme maintained, as per lasting posting(s) - its simply short term question of latitude for the high extending towards Scandinavia/Baltic. And that question is not yet answered despite what intra day model suites and accompanying tweets,from various sources, appear to achieve in terms of exaggerating the pendulum swings and associated reaction amongst sections of its audience

So, to take the excessive drama out of things, the theme of retrogression into the extended period is growing with renewed cold collecting to our NE as a result, at the same time as heights are drawn westwards across the Mediterranean to set up a -NAO. And we still don't know for sure how much cold is going to accrue within the nearer term 5 to10 day period before this.

Its really just a question of time of when the upstream energy fractionally adjusts to allow the deeper upper cold to advect across that betwixt and between little section of the NH called the UK - the bit that seems to continually be teased and promised, but appears to somehow manage to elude.

But this is where sticking with the percentage probability climatological recurrence card risks an eventual sharp burning. Taking into account the bigger picture as it is now changing, there are only so many times this mid latitude pattern can keep re-cycling with exactly the same result.

Its worth bearing in mind that what we are seeing being played out in ever closer time, is the very long term signal that the ECM extended kept playing with right back before Christmas. A time when, speaking personally, it alas seemed too premature as posted at the time for all the reasons given.

 It was on the amplified garden path wind-up then, and may still appear to keep being on the amplified garden path - but actually what is happening is that we are inching closer to that upper cold trend verifying in real time - as seen in so many of those extended suites and last nights operational (just f.e)

Happier days for NWP are here - enjoy some snow if/as/when you get it

 

 

Edited January 11, 2017 by Tamara

[Biensie]

5 minutes ago, Frosty. said:

Anyway, a lot of attention should be focussed on tomorrow, it's an upgrading situation in terms of classic rain to sleet to heavy wet snow across the south, the southeast could be the sweet spot tomorrow with a spell of heavy snow and several inches accumulating!

I would love to get excited Frosty but its hard to imagine it will lay, today its 11.5^oc and tomorrow when they say it will snow its forecast the temperature to be 7^oc

[Frosty.]

6 minutes ago, MKN said:

I know its not the most accurate but gfs doesnt predict much lying snow for most of England.

It's about potential, the risk has grown since yesterday of disruptive snow developing in the south / southeast tomorrow..a forecasting nightmare which will come down to nowcasting, it's happened before..if I lived in the south I would be getting excited about tomorrow's potential.

Edited January 11, 2017 by Frosty.

[Southender]

17 minutes ago, Frosty. said:

Anyway, a lot of attention should be focussed on tomorrow, it's an upgrading situation in terms of classic rain to sleet to heavy wet snow across the south, the southeast could be the sweet spot tomorrow with a spell of heavy snow and several inches accumulating!

After a cm or so of rain beforehand, it would have to go some to settle Frosty? I will take just seeing it fall to be honest!

[Iceaxecrampon]

06z for Thursday 12 -1-17

Forum Meltdown - server overload.

Do the Mods have a contingency plan?

 

[beefy201]

Just now, Iceaxecrampon said:

06z for Thursday 12 -1-17

Forum Meltdown - server overload.

Do the Mods have a contingency plan?

 

I can see this developing into quite some snow storm for a few areas just a feeling but watch out for some met office warnings adjustments around 11pm

[Ali1977]

Only a small move but the 06z is slightly more amplified which will again edge it slightly towards the ECM, whilst no initial Easterly feed lets see if it shows anything closer towards day 7/8 ish for the far South.

[MP-R]

Well it will either be 7C in the southeast or there will be a decent snow event, not both. As ever, this will be a now casting event and as has always been the case, altitude will be key and temperatures will be lower the further north and west.

[johnholmes]

Perhaps time, for those in the south, to try out the trusty jh ‘will it snow’ in my back garden.

Step 1

Does the model show ppn on you if not forget it, well until the next run may bring it in.

 If it does then follow the guide for about 6 or 7 parameters. Factor in your height above sea level, and also if you are very close to the coast be careful it is snow and not at best very wet snow/sleet.

Bingo

Link

 

https://www.netweather.tv/forum/topic/23729-will-it-snow/

 

also this one although I think the first is the more comprehensive

 

https://www.netweather.tv/forum/topic/27989-how-to-try-and-forecast-snow/

[frosty ground]

Corrected north slightly..... More so the Lower height below the high.

[SMU]

GFS 144 edges towards ECM ( however ECM was flatter )

low amplitude easterly - deep cold uppers not far away-

S

[Met4Cast]

06z starting to develop an Easterly feed, more amplified high, low over Europe backing Westwards. Good start to this mornings runs

 

[johnholmes]

So where is the low that MAY give snowfall for some in the southern half of England and perhaps S Wales?

 

If you look at this link for Met O Fax charts at 06z this morning it has not even started to form. By their 00z chart Thursday it is shown. Even more so by 12z but just look how complex the weather pattern is predicted to be!

By 12z Friday the various weather systems are predicted to be east of the country.

So to predict first of all where precipitation will fall is not easy, then for anyone who has looked at my ‘will it snow’ guide, you can see just how difficult it is going to be to get where, when, how much if any for any particular place. So much easier in the Alps for example.

http://www.weathercharts.org/ukmomslp.htm#t24

So watch the weather chart, link below for one site, watch the radar, watch especially if you have simply weather instruments how your dry bulb and dewpoint change as the system moves in.

http://meteocentre.com/analyse/map.php?map=eur_full&date=2017011110&size=standard&lang=en&area=eur

For the lucky ones enjoy, for the rest of us, drop some pictures in on the snow thread.

Of course other areas of the UK may also get snow, indeed already are in the north of Scotland.

http://www.winterhighland.com/cams/cairngorm-mountain/